* prefer I?ReadOnlyDictionary<,> over I?Dictionary<,>

* add field for auto prop `SplitEntities` @ RevisionWithSplitting.cs
* using primary ctor @ SaverChangeSet.cs
@ c#/crawler

Author: n0099

c#/crawler/src/Db/Revision/RevisionWithSplitting.cs

@@ -3,27 +3,29 @@ namespace tbm.Crawler.Db.Revision;
 public abstract class RevisionWithSplitting<TBaseRevision> : IRevision
     where TBaseRevision : class, IRevision
 {
+    private readonly Dictionary<Type, TBaseRevision> _splitEntities = [];
+
     public uint TakenAt { get; set; }
     public ushort? NullFieldsBitMask { get; set; }
-    public IDictionary<Type, TBaseRevision> SplitEntities { get; } = new Dictionary<Type, TBaseRevision>();
+    public IReadOnlyDictionary<Type, TBaseRevision> SplitEntities => _splitEntities;
 
     public virtual bool IsAllFieldsIsNullExceptSplit() => throw new NotSupportedException();
 
     protected TValue? GetSplitEntityValue<TSplitEntity, TValue>
         (Func<TSplitEntity, TValue?> valueSelector)
         where TSplitEntity : class, TBaseRevision =>
-        SplitEntities.TryGetValue(typeof(TSplitEntity), out var entity)
+        _splitEntities.TryGetValue(typeof(TSplitEntity), out var entity)
             ? valueSelector((TSplitEntity)entity)
             : default;
 
     protected void SetSplitEntityValue<TSplitEntity, TValue>
         (TValue? value, Action<TSplitEntity, TValue?> valueSetter, Func<TSplitEntity> entityFactory)
         where TSplitEntity : class, TBaseRevision
     {
-        if (SplitEntities.TryGetValue(typeof(TSplitEntity), out var entity))
+        if (_splitEntities.TryGetValue(typeof(TSplitEntity), out var entity))
             valueSetter((TSplitEntity)entity, value);
         else
-            SplitEntities[typeof(TSplitEntity)] = entityFactory();
+            _splitEntities[typeof(TSplitEntity)] = entityFactory();
     }
 
     public class ModelBuilderExtension(ModelBuilder builder, string baseTableName)

c#/crawler/src/Tieba/ClientRequester.cs

@@ -19,7 +19,7 @@ public class ClientRequester(
     public async Task<JsonElement> RequestJson(
         string url,
         string clientVersion,
-        IDictionary<string, string> postParam,
+        IReadOnlyDictionary<string, string> postParam,
         CancellationToken stoppingToken = default) =>
         await Request(() => PostJson(url, postParam, clientVersion, stoppingToken), stream =>
         {
@@ -84,7 +84,7 @@ private static async Task<T> Request<T>
 
     private async Task<HttpResponseMessage> PostJson(
         string url,
-        IDictionary<string, string> postParam,
+        IReadOnlyDictionary<string, string> postParam,
         string clientVersion,
         CancellationToken stoppingToken = default)
     {

c#/crawler/src/Tieba/Crawl/CrawlPost.cs

@@ -46,7 +46,8 @@ public async Task<SavedThreadsList> CrawlThreads
                 var threadsLatestReplyPostedAt = currentPageChangeSet.AllAfter
                     .Select(th => th.LatestReplyPostedAt).ToList();
                 minLatestReplyPostedAt = threadsLatestReplyPostedAt.Min();
-                if (crawlingPage == 1) _latestReplyPostedAtCheckpointCache[fid] = threadsLatestReplyPostedAt.Max();
+                if (crawlingPage == 1)
+                    _latestReplyPostedAtCheckpointCache[fid] = threadsLatestReplyPostedAt.Max();
             }
             else
             { // retry this page
@@ -98,7 +99,7 @@ await Task.WhenAll(shouldCrawlParentPosts.Select(async tid =>
     }
 
     public async Task CrawlSubReplies(
-        IDictionary<Tid, SaverChangeSet<ReplyPost>> savedRepliesKeyByTid,
+        IReadOnlyDictionary<Tid, SaverChangeSet<ReplyPost>> savedRepliesKeyByTid,
         Fid fid,
         CancellationToken stoppingToken = default)
     {

c#/crawler/src/Tieba/Crawl/Facade/BaseCrawlFacade.cs

@@ -122,7 +122,7 @@ protected virtual void ThrowIfEmptyUsersEmbedInPosts() { }
     protected virtual void PostParseHook(
         TResponse response,
         CrawlRequestFlag flag,
-        IDictionary<PostId, TPost> parsedPostsInResponse) { }
+        IReadOnlyDictionary<PostId, TPost> parsedPostsInResponse) { }
     protected virtual void BeforeCommitSaveHook(CrawlerDbContext db, UserSaver userSaver) { }
     protected virtual void PostCommitSaveHook(
         SaverChangeSet<TPost> savedPosts,

c#/crawler/src/Tieba/Crawl/Facade/SubReplyCrawlFacade.cs

@@ -24,7 +24,7 @@ public class SubReplyCrawlFacade(
     protected override void PostParseHook(
         SubReplyResponse response,
         CrawlRequestFlag flag,
-        IDictionary<PostId, SubReplyPost> parsedPostsInResponse)
+        IReadOnlyDictionary<PostId, SubReplyPost> parsedPostsInResponse)
     {
         foreach (var sr in parsedPostsInResponse.Values)
         {

c#/crawler/src/Tieba/Crawl/Facade/ThreadArchiveCrawlFacade.cs

@@ -19,7 +19,7 @@ public class ThreadArchiveCrawlFacade(
     protected override void PostParseHook(
         ThreadResponse response,
         CrawlRequestFlag flag,
-        IDictionary<PostId, ThreadPost> parsedPostsInResponse)
+        IReadOnlyDictionary<PostId, ThreadPost> parsedPostsInResponse)
     { // the second respond with flag is as same as the first one so just skip it
         if (flag == CrawlRequestFlag.ThreadClientVersion602) return;
         var data = response.Data;

c#/crawler/src/Tieba/Crawl/Facade/ThreadCrawlFacade.cs

@@ -42,6 +42,23 @@ protected override void BeforeCommitSaveHook(CrawlerDbContext db, UserSaver user
         _ = db.Users.UpsertRange(newLatestRepliersExceptLocked).NoUpdate().Run();
     }
 
+    protected override void PostParseHook(
+        ThreadResponse response,
+        CrawlRequestFlag flag,
+        IReadOnlyDictionary<PostId, ThreadPost> parsedPostsInResponse)
+    {
+        var data = response.Data;
+        if (flag == CrawlRequestFlag.ThreadClientVersion602) FillFromRequestingWith602(data.ThreadList);
+        if (flag != CrawlRequestFlag.None) return;
+        UserParser.Parse(data.UserList);
+        UserParser.ResetUsersIcon();
+        ParseLatestRepliers(data.ThreadList);
+
+        // remove livepost threads since their real parent forum may not match with current crawling fid
+        data.ThreadList.Where(th => th.LivePostType != "")
+            .ForEach(th => Posts.TryRemove((Tid)th.Tid, out _));
+    }
+
     protected void ParseLatestRepliers(IEnumerable<Thread> threads) =>
         threads.Select(th => th.LastReplyer ?? null) // LastReplyer will be null when LivePostType != ""
             .OfType<TbClient.User>() // filter out nulls
@@ -67,21 +84,4 @@ join parsed in Posts.Values on (Tid)inResponse.Tid equals parsed.Tid
             // LastReplyer will be null when LivePostType != "", but LastTimeInt will have expected timestamp value
             t.parsed.LatestReplierUid = t.inResponse.LastReplyer?.Uid;
         });
-
-    protected override void PostParseHook(
-        ThreadResponse response,
-        CrawlRequestFlag flag,
-        IDictionary<PostId, ThreadPost> parsedPostsInResponse)
-    {
-        var data = response.Data;
-        if (flag == CrawlRequestFlag.ThreadClientVersion602) FillFromRequestingWith602(data.ThreadList);
-        if (flag != CrawlRequestFlag.None) return;
-        UserParser.Parse(data.UserList);
-        UserParser.ResetUsersIcon();
-        ParseLatestRepliers(data.ThreadList);
-
-        // remove livepost threads since their real parent forum may not match with current crawling fid
-        data.ThreadList.Where(th => th.LivePostType != "")
-            .ForEach(th => Posts.TryRemove((Tid)th.Tid, out _));
-    }
 }

c#/crawler/src/Tieba/Crawl/Facade/ThreadLateCrawlFacade.cs

@@ -8,7 +8,7 @@ public class ThreadLateCrawlFacade(
     public delegate ThreadLateCrawlFacade New(Fid fid);
 
     public async Task CrawlThenSave(
-        IDictionary<Tid, FailureCount> failureCountsKeyByTid,
+        IReadOnlyDictionary<Tid, FailureCount> failureCountsKeyByTid,
         CancellationToken stoppingToken = default)
     {
         var threads = await Task.WhenAll(

c#/crawler/src/Tieba/Crawl/Saver/IRevisionProperties.cs

@@ -2,10 +2,10 @@ namespace tbm.Crawler.Tieba.Crawl.Saver;
 
 public interface IRevisionProperties
 {
-    protected static IDictionary<Type, IDictionary<string, PropertyInfo>> Cache { get; } = GetPropsKeyByType(
+    protected static IReadOnlyDictionary<Type, IReadOnlyDictionary<string, PropertyInfo>> Cache { get; } = GetPropsKeyByType(
         [typeof(ThreadRevision), typeof(ReplyRevision), typeof(SubReplyRevision), typeof(UserRevision)]);
 
-    private static IDictionary<Type, IDictionary<string, PropertyInfo>> GetPropsKeyByType(IEnumerable<Type> types) =>
+    private static IReadOnlyDictionary<Type, IReadOnlyDictionary<string, PropertyInfo>> GetPropsKeyByType(IEnumerable<Type> types) =>
         types.ToDictionary(type => type, type =>
-            (IDictionary<string, PropertyInfo>)type.GetProperties().ToDictionary(prop => prop.Name));
+            (IReadOnlyDictionary<string, PropertyInfo>)type.GetProperties().ToDictionary(prop => prop.Name));
 }

c#/crawler/src/Tieba/Crawl/Saver/SaverChangeSet.cs

@@ -2,27 +2,24 @@
 
 namespace tbm.Crawler.Tieba.Crawl.Saver;
 
-public class SaverChangeSet<TPost> where TPost : class, IPost
+public class SaverChangeSet<TPost>(
+    IReadOnlyCollection<TPost> existingBefore,
+    ICollection<TPost> existingAfterAndNewlyAdded,
+    Func<TPost, PostId> postIdSelector)
+    where TPost : class, IPost
 {
-    public SaverChangeSet(
-        IReadOnlyCollection<TPost> existingBefore,
-        ICollection<TPost> existingAfterAndNewlyAdded,
-        Func<TPost, PostId> postIdSelector)
-    {
-        Existing = existingBefore
-            .OrderBy(postIdSelector)
-            .EquiZip(existingAfterAndNewlyAdded
+    public IReadOnlyCollection<(TPost Before, TPost After)> Existing { get; } = existingBefore
+        .OrderBy(postIdSelector)
+        .EquiZip(existingAfterAndNewlyAdded
                 .IntersectBy(existingBefore.Select(postIdSelector), postIdSelector)
                 .OrderBy(postIdSelector),
-                (before, after) => (before, after))
-            .ToList().AsReadOnly();
-        NewlyAdded = existingAfterAndNewlyAdded
-            .ExceptBy(existingBefore.Select(postIdSelector), postIdSelector)
-            .ToList().AsReadOnly();
-        AllAfter = existingAfterAndNewlyAdded.ToList().AsReadOnly();
-    }
+            (before, after) => (before, after))
+        .ToList().AsReadOnly();
 
-    public IReadOnlyCollection<(TPost Before, TPost After)> Existing { get; }
-    public IReadOnlyCollection<TPost> NewlyAdded { get; }
-    public IReadOnlyCollection<TPost> AllAfter { get; }
+    public IReadOnlyCollection<TPost> NewlyAdded { get; } = existingAfterAndNewlyAdded
+        .ExceptBy(existingBefore.Select(postIdSelector), postIdSelector)
+        .ToList().AsReadOnly();
+
+    public IReadOnlyCollection<TPost> AllAfter { get; } = existingAfterAndNewlyAdded
+        .ToList().AsReadOnly();
 }